Ball bats, such as baseball and softball bats, are well known. In recent years, metallic bats including a tubular handle portion and a tubular hitting portion have emerged providing improved performance and improved durability over crack-prone wooden bats. The most common tubular bat is the aluminum single-wall tubular bat. Such bats have the advantage of a generally good impact response, meaning that the bat effectively transfers power to a batted ball.
Generally speaking, bat performance is a function of the weight of the bat, the size, and the impact response of the bat. The durability of a bat relates, at least in part, to its ability to resist denting and depends on the strength and stiffness of the tubular bat frame. While recent innovations in bat technology have increased performance and durability, most new bat designs typically improve performance or durability at the expense of the other because of competing design factors. For example, an attempt to increase the durability of the bat often produces an adverse effect on the bat's performance.
Another example of competing design factors concerns the bat's optimum hitting area, commonly referred to as the “sweet spot.” The sweet spot is typically located near the center of the impact area of the bat. The performance of the bat typically drops off considerably when a ball impacts the bat outside the sweet spot, for example, near the end of the bat. When this occurs, the batter can feel greater vibration and less energy is transferred from the bat to the ball. An obvious way to increase the sweet spot of a bat is to increase the length and/or circumference of the bat. This option is constrained by institutional rules and regulations, as well as by the personal preferences and expectations of ball players. In addition, an increase in the overall size of the bat undesirably adds weight, often causing reduced bat speed and less slugging distance.
In the early 1990's, DeMarini Sports revolutionized the design of existing ball bats with the introduction of a multi-wall bat. The multi-wall bat comprised two tubular members (the tubular hitting portion of the bat and a second tubular member coaxially aligned with the hitting portion of the bat), wherein each tubular member is configured to move independently in response to an impact with a ball in a manner characteristic of a leaf spring. This design described in U.S. Pat. No. 5,415,398 significantly improved the impact response of the bat without adding detrimental weight or unnecessarily increasing the length or diameter of the ball bat. The disclosure of incorporated by reference U.S. Pat. No. 5,415,398 is incorporated by reference.
The incorporation of these advances, other design variations and the use of additional materials, such as, other aluminum alloys, titanium alloys and composite materials have resulted a large variety of well-performing ball bats. Despite such advances in ball bat design and materials, a continuing need exists to further improve the performance, durability and feel of existing bats.
One issue affecting high performance ball bats is the introduction of performance restrictions on ball bats by many of the Industry regulatory organizations governing organized play. Many of these organizations have imposed limitations or restrictions impose limits on the maximum responsiveness of the ball bat when impacted at the sweet spot of the ball bat. Not surprisingly, many existing bats, which were reconfigured to meet these restrictions, exhibit a significant reduction in overall bat performance due to the added weight, additional wall thickness, the lack of leaf spring independent movement between multi-walls of a ball bat, or other factors.
Thus, a continuing need exists for a ball bat, which can satisfy existing performance restrictions and provide an improved overall bat slugging performance. What is needed is a ball bat having an enlarged sweet spot providing improved bat slugging performance over a wider area of the hitting portion of the ball bat. It would be advantageous to produce a ball bat with an enlarged sweet spot without negatively affecting the reliability or durability of the ball bat. It would also be advantageous to produce a bat that meets Industry restrictions and provides optimum performance without negatively affecting the weight distribution or moment of inertial (“MOI”) of the ball bat.